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Entry type: Application example Entry ID: 109763709, Entry date: 05/28/2019

Function blocks and faceplates for evaluation of the diagnostic interface "COM" of the SITOP SEL1200/SEL1400 and visualization of the device data

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  • Associated product(s)
The selectivity modules SITOP SEL1200 and SEL1400 have a diagnostic interface "COM" whose signal can be evaluated via a digital input in a high-lever controller, e. g. S7-1200 CPU and S7-1500 CPU.

The diagnostic interface "COM" of the SEL1200 and SEL1400 provides a signal that transmits the following device data as a Manchester code:

  • Status information
  • Current output current values at the outputs
  • Current limit values at the outputs
  • Device information

The following library provides function blocks for SIMATIC S7-1200, S7-1500 and S7-300/S7-400 as well as faceplates for SIMATIC Comfort Panels. The function blocks enable you to read in and evaluate the signal of the diagnostic interface "COM" via a digital input at the S7-CPU. You can use the faceplates to clearly display the device data on an HMI control panel.


  • The library blocks for SIMATIC S7-1500 can also be used in an ET 200SP CPU and ET 200pro CPU.
  • The library blocks for SIMATIC S7-300/S7-400 can also be used in an ET 200S CPU and ET 200pro CPU.

The following figure shows the graphic representation of the solution.

Fig. 1

1Power supply
2CPU with function block (FB)
3Digital input module / Digital output module (DI / DO)
4Diagnostic interface "COM"
5RESET input "RST"
6Output 1 to 8 24 V DC
7Input 24 V DC

Table 1

  Documentation Library "LSEL_V15.0-0_V1-0-0" (3,3 MB)
 Registrierung notwendig  Library for STEP 7 V15 (3,7 MB)

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